Yahoo is adding to its mobile lineup with the acquisition of analytics company Flurry.

Yahoo is paying more than $300 million for the San Francisco-based startup, according to people with knowledge of the matter, who asked not to be identified because the talks were private. Flurry analyzes data from smartphone users to help developers better understand their audiences, and connects brands and agencies to consumers on devices through targeted advertising, giving Yahoo more pathways for mobile promotions.

Yahoo Chief Executive Officer Marissa Mayer, who has called mobile a key part of her turnaround effort, has stepped up her dealmaking as she looks to jump start growth at the Web portal. The Sunnyvale-based company last year spent about $1.1 billion on blogging platform Tumblr and has since bought several smaller companies, including mobile-homescreen provider Aviate and video-distribution platform RayV. Yahoo has announced or completed at least 12 acquisitions this year, according to data compiled by Bloomberg.

“It ties right into Yahoo and mobile first and all of the investments we’re making into mobile today,” Scott Burke, Yahoo’s senior vice president of advertising technology, said in an interview. “Flurry is the next logical step to extend our reach. They have a great brand.”

He declined to comment on the size of the deal, which was earlier reported by technology blog TechCrunch. Flurry will continue serving customers while collaborating with some of Yahoo’s services, including advertising features, Burke said, without being specific.

Yahoo last week reported second-quarter results that included a 4.5 percent sales decline from a year earlier. Revenue, excluding that shared with partner websites, was $1.04 billion, missing analysts’ average estimate of $1.09 billion, according to data compiled by Bloomberg.

Mobile was a bright spot. Mayer said revenue from graphically based ads on portable devices more than doubled during the quarter, with mobile users growing to about 450 million, up from slightly more than 200 million two years ago.

With the deal, Flurry will gain the resources of a larger company and experience in ramping up services to bigger audiences, CEO Simon Khalaf said in an interview. More than 170,000 developers use data from Flurry.

“This is a commitment to work with the app developer community on helping them build better applications, helping them monetize,” Khalaf said.

Flurry has raised more than $60 million from backers including Union Square Ventures, DFJ and Menlo Ventures. Its customers include Pinterest and Snapchat.

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